1. Field of the Invention
The present invention relates to a polymer blend, and more particularly to a molecular blended polymer which includes two or more types of polymers blended at the molecular level.
2. Background of the Invention
In order to improve the properties of a single polymer, blending two or more types of polymers to obtain a polymer blend is a frequently-used technique.
For example, Picchioni et al. prepare a blend of syndiotactic polystyrene and SBS triblock copolymer by mechanical mixing and solution casting (Macromol. Chem. Phys. 2001, 202, 2142-2147). Xu et al. prepare a blend of syndiotactic polystyrene and isotactic polypropene using two different Ziegler-Natta catalysts (Macromol. Chem. Phys. 2001, 202, 1817-1823). Abis et al. prepare a blend of syndiotactic polystyrene and high density polyethylene using SEBS copolymer as a compatibilizer (Macromol. Chem. Phys. 2000, 201, 1732-1741).
However, the conventional polymer blend suffers from phase separation. In addition, for the polymer blend prepared by polymerizing two monomers using two catalysts (for example, in the above Xu's paper), the polymerization is not well-controlled. Thus, the microstructure and physical properties of the polymer are adversely affected.